4/x - 4/y =

Question

I know the answer is 4y-4x/xy but how would I figure out a similar question? I mean why is that answer?

Answer 1

For fractions to be added or divided they must have the same denominator.

 

Example:

 

1/2 + 1/4

2/4 + 1/4 

3/4

 

If a common denominator cannot be found by multiplying one or both by the same number, multiplying by each other works

 

1/3 + 1/5

5/15 + 3/15

8/15

 

So it is with the problem given. Not knowing a multiple that "x" and "y" have in common, the common denominator is their product.

 

 

Answer 2

Meridith:

 

U need to use the same principle, that is applying the LCM principle to both fractions.

 

4/x - 4/y = 4/x - 4/y

                

             =  4.y - 4.x

                      xy

             =  4y - 4x

                     xy

 

Meridith you will be fine, your biggest challenge is to determine the LCM (Least or Lowest Common Multiple) for any similar problem.

 

 

Frank